Explain the Procedure for Preparation of Bacterial Smear?
Start the exercise by following the steps enumerated herewith.
(1) Take properly washed and dried glass slides for making bacterial smear. If slides are oily or greasy, wash them properly with soap and water followed by water rinse and a rinse with 95% alcohol. The slides are then dried.
(2) Now, label the slides properly by writing organism's name on either end of the slide by glassware marking pencil or permanent marker.
(3) Prepare the bacterial smear by using either liquid or solid culture medium as discussed herewith. From Liquid Culture - Re-suspend the sedimented cells in broth culture by tapping the culture tube with finger. Spread one or two loopfuls of the culture with a sterile inoculating loop over the center of the slide. Allow smear to air dry. From Solid Culture - Place a loopful of water over the center of the slide. Transfer the culture to the drop with a sterile, cooled loop. Mix small amount of cells with this drop and spread in a circular motion of the loop. Allow smear to air dry completely. The smear should appear as semitransparent or translucent whitish film.
(4) Fix the bacterial smear on glass slide by heat fixation. This can be accomplished by rapid passage of air-dried smear over the Bunsen burner flame two-three times. So you have done this. The slide is ready for staining.
(5) Examine each slide for the confluent, whitish film or haze.